Articles made of thermoplastic resin are sometimes required to have surfaces with high scratch resistance. In order to protect the surface of an article, a protective sheet may be provided on the surface of the article. Such a protective sheet is required to be excellent in thermoformability and also in scratch resistance as a surface layer of an article. For example, JP 2000-326446 A discloses a decorative sheet as a product designed to be used as such a protective sheet, the decorative sheet comprising a thermoplastic sheet and a surface protective layer provided thereon wherein the surface protective layer is made of a ionizing radiation-curable resin.
In order to obtain an article having such a decorative sheet provided on the surface of a thermoplastic resin substrate, however, it is necessary to precisely control the compounding ratio of a hardening component in a composition to be used for the formation of a surface protective layer, mixing-dispersing conditions in the preparation of the composition, energy line irradiation conditions for curing the surface protective layer, etc.